The terrain is mostly an arid plateau (c.3,000 ft/910 m high); in the east are hills. The Kalahari Desert lies in the south and west. In the northwest the Okavango (Cubango) River drains into the vast region of the Okavango Delta and Lake Ngami, thus forming a huge marshland. Rainfall varies from less than 9 in. (23 cm) per year in the southwest to about 25 in. (64 cm) in the north. The climate is subtropical, but droughts are common.
The country's population is mainly Tswana, who speak a Bantu language and are divided into eight major groups. There are also small minorities of Kalanga, Basarwa, Kgalagadi, and other poeples. English is the official language, but Tswana is also widely spoken. More than 70% of the population follow Christianity and about 10% adhere to traditional practices.